FIMGBIN (Jan91) ftools.fimage FIMGBIN (Jan91)
NAME
fimgbin -- Rebin a FITS image using a rectangular bin size
USAGE
fimgbin input output xbinsize
PARAMETERS
infile [file name]
Input FITS file and extension number to be convolved with the
rectangular boxcar filter.
outfile [file name]
Output FITS file where the convolved image will be written.
xbinsize [integer]
The number of pixels in the X direction to be binned together
into the single pixel of the outfile.
(ybinsize = 0) [integer]
The number of pixels in the Y direction to be binned together
into the single pixel of the outfile. A value less than 1
causes ybinsize to be the same as the xbinsize. This is the
default.
(datatype = "-") [character]
The data type for the resulting smoothed image. If blank or "-",
defaults are to the bitpix of the input image.
Acceptable inputs are (b,8), (i,short,16), (j,integer,int,long,32),
(r,f,e,real,float,-32) and (d,double,-64). They are case-insensitive.
(overflow = no) [boolean]
Whether to ignore the overflow and underflow in the output file.
If true, the overflow and underflow elements of the output image
array will be ignored and replaced with the maximum and minimum
of the corresponding data type. If false, these elements will throw
an error and terminate the program. This option is only relevant
for byte, short and integer images.
(nullval = 0.0) [double]
Value to substitute for any undefined pixels within the image.
(average = no) [boolean]
This flag is used to cause the pixel count in the output bin to
be normalized by the number of pixels binned up into one
(average). By default the pixel count is simple summed.
(copyprime = yes) [boolean]
If true, all of the primary header keywords, the primary array
(if any) and all of the extension keywords of the first input
file are copied to the output file. If false, only minimal
headers are created.
(copyall = no) [boolean]
If true, all other extensions, including the primary array are
copied to the output file.
(clobber = no) [boolean]
If true, an existing output file of the same name will be
overwritten.
DESCRIPTION
FIMGBIN rebins an image by summing the values in each xbinsize by
ybinsize region of the infile into a single value of the outfile.
The ybinsize is a hidden parameter and when its value is less than
1, it defaults to the same size as the xbinsize. Any pixels in the
infile around the right or lower boundaries that do not conform to
an integer number of bins will be left out of the output file. In
order to preserve all pixels of the input image in the output image
the image dimension must be divisible by the xbinsize and ybinsize
parameters.
EXAMPLES
1. Rebin an image so that each square of 4 by 4 pixels is binned up
into a single pixel.
cl> fimgbin image.fits rebin.fits 4
2. Rebin an image so that each square of 3 by 4 pixels is binned up
into a single pixel and the resulting datatype for the image is
real.
cl> fimgbin img.fits rbimg.fits 3 ybinsize=4 datatype='e'
BUGS
SEE ALSO
fboxcar